The present invention relates to the manufacture of heat exchangers and to a novel and particular heat exchanger.
The manufacture of heat exchangers which are particularly usable for cooling engines conventionally uses tubes of circular section which are engaged into bundles of fins into which they are then inflated. In some known embodiments, the tube-plates ae then set in place on the ends of the tubes which protrude beyond the fins, so that subsequent inflation provides the mutual fixation of the tubes and tube-plates.
In order to insure a good tight fit, a flexible gasket is most often interposed between the outer wall of the tubes and collars formed on the tube-plates. Headers are thereafter fixed by means of tongs or clips or by crimping on the tube-plates.
The hereabovementioned embodiment gives relative satisfaction but is costly since it requires two inflating operations of the tubes, and successive manipulations since, in addition to the successive inflations of the tubes, the crimping or other fastening of the headers on the tube-plates has to be carried out subsequently.
In another known embodiment, the tubes are inflated simultaneously in tube-plates and a bundle of fins, and then tie rods are interposed between the tube-plates so that the distance between said tube-plates remains constant even after a prolonged usage, viz. after a large number of expansion and contraction cycles of tubes.
Another known embodiment involves inflating the tubes in a bundle of fins and then in forcibly inserting tube-plates provided with resilient sockets onto the protruding ends of the tubes. In this last embodiment, the tube-plate can comprise a separate insert header or may be formed by the wall of a hollow body forming both a header and a tube plate.
This last embodiment is the most simple but it can happen sometimes that the tube-plates are displaced relative to the tubes of the core since they are held simply by friction of the resilient sockets against the wall of the tube ends.